public static AccessGraph convertToSingleColumnEdges(Database catalog_db, AccessGraph orig_agraph) {
AccessGraph agraph = new AccessGraph(catalog_db);
Map<CatalogPair, DesignerEdge> entry_edges = new HashMap<CatalogPair, DesignerEdge>();
for (DesignerVertex v : orig_agraph.getVertices()) {
agraph.addVertex(v);
} // FOR
for (DesignerEdge e : orig_agraph.getEdges()) {
// Split up the ColumnSet into separate edges, one per entry
PredicatePairs cset = e.getAttribute(EdgeAttributes.COLUMNSET);